Best for
Dry or dehydrated skin — suits all skin types
Typical concentration
Around 1% in most serums
Pairs well with
Hyaluronic acid
Polyglutamic acid (PGA) is a newer hydrating ingredient made from fermented amino acid chains, often marketed as an alternative or companion to hyaluronic acid. Both are excellent humectants, but they work in genuinely different ways — understanding the difference actually matters here, since they’re often positioned as competitors rather than complements.
What polyglutamic acid does for skin
- Forms a protective surface layer — rather than penetrating deep into skin the way hyaluronic acid does, PGA forms a film on the surface that locks in moisture and slows water loss
- Boosts natural moisturizing factors (NMFs) — helps strengthen the skin’s own ability to retain moisture over time
- Reduces the appearance of fine lines — through sustained surface hydration, skin appears plumper and smoother
- Improves elasticity with long-term use — research suggests PGA can help prevent moisture loss over longer periods than hyaluronic acid alone
You’ll often see PGA advertised as holding “4x,” “4,000x,” or even “5,000x” more water than hyaluronic acid. These figures vary considerably between sources and aren’t consistently sourced to independent, comparable studies — treat the exact multiple with some skepticism. What’s more reliably supported is the underlying mechanism: PGA works as a surface-level film-former with strong water-retention properties, a genuinely different (and complementary) mechanism to hyaluronic acid’s deeper-penetrating hydration.
How much polyglutamic acid should you use
Most formulated serums use PGA at low concentrations (often around 1%), sometimes blending multiple molecular weights — lower molecular weight PGA can penetrate slightly below the surface, while higher molecular weight PGA sits on top forming the protective film. As with hyaluronic acid, apply to damp skin and follow with a moisturizer to seal in the hydration effectively.
Who should use polyglutamic acid
Particularly beneficial for dry or dehydrated skin wanting an extra layer of surface hydration, and works well for all skin types as a complement to hyaluronic acid rather than a replacement. Those in very dry or air-conditioned environments may notice PGA’s surface-sealing effect especially useful.
What to pair polyglutamic acid with
PGA and hyaluronic acid are frequently used together specifically because they work at different levels. This combination is considered more effective than either ingredient alone for comprehensive hydration.
Frequently asked questions
Is polyglutamic acid better than hyaluronic acid?
Neither is strictly “better” — they work through different mechanisms (surface film-forming vs. deeper penetration) and are often more effective when used together than as a substitute for one another.
Does polyglutamic acid really hold thousands of times more water than hyaluronic acid?
The specific multiples cited vary widely across sources and marketing materials — the underlying water-retention mechanism is real, but treat exact figures with some caution rather than taking a specific number at face value.
Can I use polyglutamic acid every day?
Yes, it’s generally considered gentle and suitable for daily use.
Is polyglutamic acid good for oily skin?
Yes — like hyaluronic acid, it’s a humectant rather than an oil, so it hydrates without adding greasiness, making it suitable for oily and acne-prone skin too.